No trip to Oahu is complete without a visit to Hanauma Bay on the south shore of this beautiful Hawaiian Island. Whether you are going to snorkel or simply look down at one of nature’s wonders from the lookout point above – this is a definite must see natural attraction in Hawaii.
To get there, head south from Honolulu and Waikiki. You will go around Diamond Head, through the neighborhood of Kahala, and on through the neighborhoods of Aina Haina and Hawaii Kai before reaching the turn just as you are passing Koko Head. Hanauma means ‘curved bay’ in Hawaiian languange and this is a beautiful coral filled bay in the remains of a tuff cone volcano. Not your average snorkel spot.
Hanauma Bay is a Nature Preserve and Marine Life Conservation District. It is open to the public six days per week with the seventh day reserved for park maintenance – or as we say in Hawaii – to let the fish rest. To enter the bay, you will need to attend a short environmental presentation that teaches you how to respect and appreciate the beauty of nature in the bay. Visitors are not allowed to touch fish, marine life, or walk on the corals in Hanauma.
Hanauma Bay is home to Hawaiian green sea turtles and over 400 species of fish including parrotfish, rasses, and even the famous humuhumunukunukuapua’a. Global warming has exacted a terrible cost on the bay and nearly half of the corals in it have died as a result.
Hanauma Bay itself was born about 32,000 years ago. It was one of the last eruptions on this island. A crater was formed and eventually waves broke through and flooded it creating the perfect environment for corals and fish. Hawaiian Kings and Queens frequented the bay and one possible interpretation of the name is that there were a variety of sporting and wrestling events held there each year at makahiki. The bay belonged to the Bishop Estate until the 1930s when it was purchased by the City and County of Honolulu. It became a protected area in 1967. In the 1970s white sand was brought in from the North Shore to create the beach you see there today.
The area was overused and suffering greatly up until the early 2000’s when the city enacted an entrance fee, closed the park on Tuesdays, and began requiring visitors to attend the educational presentation. The city has also restricted how many vehicles and how visitors can come to the bay. Commercial vehicles are strictly regulated.
Hanauma Bay can still be crowded with nearly 3000 visitors each day. If you are going, bring reef friendly sunscreen, water, and it is recommeneded that you bring your own snorkel gear as the rentals on site will cost you almost as much as buying a new set of gear.
South East of 
I’ve always thought that the Halona Blowhole, and blowholes in general, are very unfortunately named. They should instead be called ocean geysers or lava tube spouts – but blowhole? Really? Oh well, there’s nothing I can do about it. The unfortunate name doesn’t change the fact that the Halona Blowhole is one of Oahu’s most exciting natural wonders. Like 
